ON THIS PAGE: You will learn about how doctors describe a cancer’s growth or spread. This is called the stage. To see other pages, use the menu on the side of your screen.

Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting other parts of the body. Doctors use diagnostic tests to find out the cancer's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis, which is the chance of recovery.

There are different stage descriptions for different types of cancer. This section covers staging of adenocarcinoma, the most common type of stomach cancer. Staging is different for gastric lymphoma[3], sarcoma[4], and carcinoid tumors[5].

TNM staging system

One tool that doctors use to describe the stage is the TNM system. Doctors use the results from diagnostic tests and scans to answer these questions:

Tumor (T): How deeply has the primary tumor spread into the stomach wall?

Node (N): Has the tumor spread to the lymph nodes? If so, where and how many?

Metastasis (M): Has the cancer metastasized to other parts of the body?

The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.

Here are more details on each part of the TNM system for stomach cancer:

Tumor (T)

Using the TNM system, the “T” plus a letter or number (0 to 4) is used to describe the how far the tumor has grown into the stomach wall. Some stages are also divided into smaller groups that help describe the tumor in even more detail. Specific tumor stage information is listed below:

TX: The primary tumor cannot be evaluated.

T0 (T plus zero): There is no evidence of a primary tumor in the stomach.

Tis: This stage describes a condition called carcinoma (cancer) in situ. The cancer is found only in cells on the surface of the inner lining of the stomach called the epithelium and has not spread to any other layers of the stomach.

T1: The tumor has grown into the lamina propria, muscularis mucosae, or the submucosa, which are the inner layers of the wall of the stomach.

T1a: The tumor has grown into the lamina propria or muscularis mucosae.

T1b: The tumor has grown into the submucosa.

T2: The tumor has grown into the muscularis propria, the muscle layer of the stomach.

T3: The tumor has grown through all of the layers of the muscle into the connective tissue outside the stomach, but it has not grown into the lining of the abdomen, called the peritoneal lining, or into the serosa, which is the outer layer of the stomach.

T4: The tumor has grown through all of the layers of the muscle into the connective tissue outside the stomach and has grown into the peritoneal lining or serosa or the organs surrounding the stomach.

T4a: The tumor has grown into the serosa.

T4b: The tumor has grown into organs surrounding the stomach.

Node (N)

The “N” in the TNM staging system is for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes inside the abdomen are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes. The overall prognosis for patients with stomach cancer is based on how many regional lymph nodes show signs of cancer. If two or fewer have cancer, the prognosis is better than if more than if three to six or seven or more lymph nodes contain cancer cells.

NX: Regional lymph nodes cannot be evaluated.

N0 (N plus zero): The cancer has not spread to the regional lymph nodes.

N1: The cancer has spread to one to two regional lymph nodes.

N2: The cancer has spread to three to six regional lymph nodes.

N3: The cancer has spread to seven or more regional lymph nodes.

N3a: The cancer has spread to seven to 15 regional lymph nodes.

N3b: The cancer has spread to 16 or more regional lymph nodes.

Metastasis (M)

The “M” in the TNM system indicates whether the cancer has spread to other parts of the body, called distant metastasis.

MX: Distant metastasis cannot be evaluated.

M0 (M plus zero): The cancer has not spread to other parts of the body.

M1: The cancer has spread to another part or parts of the body.

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classifications.

Stage 0: This is also called carcinoma in situ. The cancer is found only on the surface of the epithelium. The cancer has not grown into any other layers of the stomach and is considered an early cancer (Tis, N0, M0).

Stage IA: The cancer has grown into the inner layer of the wall of the stomach, but it has not spread to any lymph nodes or other organs (T1, N0, M0).

Stage IB: Stomach cancer is called stage IB in either of these two conditions:

The cancer has grown into the inner layers of the wall of the stomach and has spread to one to two lymph nodes but not elsewhere (T1, N1, M0).

The cancer has grown into the outer muscular layers of the wall of the stomach, but the cancer has not spread to the lymph nodes or other organs (T2, N0, M0).

Stage IIA: Stomach cancer is called stage IIA for any one of these conditions:

The cancer has grown into the inner layer of the wall of the stomach and has spread to three to six lymph nodes but not elsewhere (T1, N2, M0).

The cancer has grown into the outer muscular layers of the wall of the stomach and has spread to one to two lymph nodes but not elsewhere (T2, N1, M0).

The cancer has grown through all of the layers of the muscle into the connective tissue outside the stomach but has not grown into the peritoneal lining or serosa. It has not spread to any lymph nodes or surrounding organs (T3, N0, M0).

Stage IIB: Stomach cancer is called stage IIB for any one of these conditions:

The cancer has grown into the inner layers of the wall of the stomach and has spread to seven or more lymph nodes but not elsewhere. (T1, N3, M0).

The cancer has invaded the outer muscular layers of the wall of the stomach and has spread to three to six lymph nodes but not elsewhere (T2, N2, M0).

The cancer has grown through all of the layers of the muscle into the connective tissue outside the stomach but has not grown into the peritoneal lining or serosa and has spread to one to two lymph nodes but not elsewhere (T3, N1, M0).

The cancer has grown through all of the layers of the muscle into the connective tissue outside the stomach and has grown into the peritoneal lining or serosa, but it has not spread to any lymph nodes or surrounding organs (T4a, N0, M0).

Stage IIIA: Stomach cancer is called stage IIIA for any one of these conditions:

The cancer has grown into the outer muscular layers of the stomach wall and has spread to seven or more lymph nodes but not to other organs (T2, N3, M0).

The cancer has grown through all of the layers of the muscle into the connective tissue outside the stomach but has not grown into the peritoneal lining or serosa. It has spread to three to six lymph nodes but not to other organs (T3, N2, M0).

The cancer has grown through all of the layers of the muscle into the connective tissue outside the stomach and has grown into the peritoneal lining or serosa and has spread to one to two lymph nodes but not to other organs (T4a, N1, M0).

Stage IIIB: Stomach cancer is called stage IIIB for any of these conditions:

The cancer has grown through all of the layers of the muscle into the connective tissue outside the stomach but has not grown into the peritoneal lining or serosa. It has spread to seven or more lymph nodes but has not invaded any surrounding organs (T3, N3, M0).

The cancer has grown through all of the layers of the muscle into the connective tissue outside the stomach and has grown into the peritoneal lining or serosa and has spread to three to six lymph nodes but has not spread elsewhere (T4a, N2, M0).

The cancer has grown through all of the layers of the muscle into the connective tissue outside the stomach and has grown into nearby organs or structures. It may or may not have spread to one to two lymph nodes but not to distant parts of the body (T4b, N0 or N1, M0).

Stage IV: Stage IV stomach cancer describes a cancer of any size that has spread to distant parts of the body in addition to the area around the stomach (any T, any N, M1).

Recurrent cancer: Recurrent cancer is cancer that has come back after treatment. It may be a localized recurrence, meaning it comes back in the place where it started, or it may be a distant metastasis, which means it comes back in another part of the body. If the cancer does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis[6].

Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition published by Springer-Verlag New York, www.cancerstaging.net[7].

Japanese staging system

Stomach cancer is much more common in Japan and other parts of Asia and South America than in the United States. Japan has a different method of staging stomach cancer, based on where the lymph nodes with cancer are located around the stomach. This is different from the U.S. system, which uses the number of lymph nodes and not their location.

Surgery for stomach cancer may be described using the Japanese system. The type of surgery is identified by which lymph nodes are removed in addition to the stomach. Learn more about surgery for stomach cancer in the Treatment Options[8] section.

D0: no lymph nodes were removed

D1: the lymph nodes closest to the stomach were removed

D2: lymph nodes from a wider area were removed

Information about the cancer’s stage will help the doctor recommend a specific treatment plan. The next section in this guide is Treatment Options[8]. Or, use the menu on the side of your screen to choose another section to continue reading this guide.